Renal macrophages induce hypertension and kidney fibrosis in Angiotensin II salt mice model.

The immune system is involved in hypertension development with different immune cells reported to have either pro or anti-hypertensive effects. In hypertension, immune cells have been thought to infiltrate blood pressure-regulating organs, resulting in either elevation or reduction of blood pressure. There is controversy over whether macrophages play a detrimental or beneficial role in the development of hypertension, and the few existing studies have yielded conflicting results. This study aimed to determine the effects of angiotensin II (Ang II) salt-induced hypertension on renal immune cells and to determine whether renal macrophages are involved in the induction of hypertension. Hypertension was induced by administration of Ang II and saline for two weeks. The effects of hypertension on kidney immune cells were assessed using flow cytometry. Macrophage infiltration in the kidney was assessed by immunohistochemistry and kidney fibrosis was assessed using trichrome stain and kidney real time-qPCR. Liposome encapsulated clodronate was used to deplete macrophages in C57BL/6J mice and investigate the direct role of macrophages in hypertension induction. Ang II saline mice group developed hypertension, had increased renal macrophages, and had increased expression of Acta2 and Col1a1 and kidney fibrotic areas. Macrophage depletion blunted hypertension development and reduced the expression of Acta2 and Col1a1 in the kidney and kidney fibrotic areas in Ang II saline group. The results of this study demonstrate that macrophages infiltrate the kidneys and increase kidney fibrosis in Ang II salt-induced hypertension, and depletion of macrophages suppresses the development of hypertension and decreases kidney fibrosis. This indicates that macrophages play a direct role in hypertension development. Hence macrophages have a potential to be considered as therapeutic target in hypertension management.

Swallowing-related muscle inflammation and fibrosis induced by a single dose of radiation exposure in mice.

BACKGROUND: Although radiotherapy is commonly used to treat head and neck cancer, it may lead to radiation-associated dysphagia (RAD). There are various causes of RAD, however, the mechanism has not yet been fully identified. Currently, the only effective treatment for RAD is rehabilitation. Additionally, there are few available animal models of RAD, necessitating the development of new models to establish and evaluate RAD treatments. We hypothesize that radiation-induced neck muscle fibrosis could be one of the causes of RAD due to impairment of laryngeal elevation. Therefore, in this study, we focused on the changes in inflammation and fibrosis of the strap muscles (Sternohyoid, Sternothyroid, and Thyrohyoid muscles) after a single-dose irradiation. This research aims to provide a reference animal model for future studies on RAD. RESULTS: Compared to control mice, those treated with 72-Gy, but not 24-Gy, irradiation had significantly increased tumor necrosis factor-α (TNF-α) (p < 0.01) and α-smooth muscle actin (αSMA) (p < 0.05) expression at 10 days and significantly increased expression levels of motif chemokine ligand-2 (CCL2), α-SMA, tumor growth factor-ß1 (TGF-ß1), type1 collagen, and interleukin-1ß (IL-1ß) (p < 0.05) in the muscles at 1 month by real-time PCR analysis. The results of immunohistochemistry showed that the deposition of type 1 collagen gradually increased in extracellular space after radiation exposure, and the positive area was significantly increased at 3 months compared to non-irradiated control. CONCLUSIONS: A single dose of 72-Gy irradiation induced significant inflammation and fibrosis in the strap muscles of mice at 1 month, with immunohistochemical changes becoming evident at 3 months. This cervical irradiation-induced fibrosis model holds potential for establishing an animal model for RAD in future studies. LEVEL OF EVIDENCE: N/A.

Bone marrow stromal cell antigen-1 deficiency protects from acute kidney injury.

This study aimed to investigate the role of bone marrow stromal cell antigen-1 (Bst1; also known as CD157) in acute kidney injury (AKI). Bst1 is a cell surface molecule with various enzymatic activities and downstream intracellular signaling pathways that modulate the immune response. Previous research has linked Bst1 to diseases such as ovarian cancer, Parkinson's disease, and rheumatoid arthritis. We used bilateral ischemia-reperfusion injury (IRI) as an AKI model and created bone marrow chimeric mice to evaluate the role of Bst1 in bone marrow-derived cells. We also used flow cytometry to identify Bst1/CD157 expression in hematopoietic cells and evaluate immune cell dynamics in the kidney. The findings showed that Bst1-deficient (Bst1-/-) mice were protected against renal bilateral IRI. Bone marrow chimera experiments revealed that Bst1 expression on hematopoietic cells, but not parenchymal cells, induced renal IRI. Bst1 was mainly found in B cells and neutrophils by flow cytometry of the spleen and bone marrow. In vitro, migration of neutrophils from Bst1-/- mice was suppressed, and adoptive transfer of neutrophils from wild-type Bst1+/+ mice abolished the renal protective effect in Bst1 knockout mice. In conclusion, the study demonstrated that Bst1-/- mice are protected against renal IRI and that Bst1 expression in neutrophils plays a crucial role in inducing renal IRI. These findings suggest that targeting Bst1 in neutrophils could be a potential therapeutic strategy for AKI.NEW & NOTEWORTHY Acute kidney injury (AKI), a serious disease for which there is no effective Federal Drug Administration-approved treatment, is associated with high mortality rates. Bone marrow stromal cell antigen-1 (Bst1) is a cell surface molecule that can cause kidney fibrosis, but its role in AKI is largely unknown. Our study showed that Bst1-/- mice revealed a protective effect against renal bilateral ischemia-reperfusion injury (IRI). Adoptive transfer studies confirmed that Bst1 expression in hematopoietic cells, especially neutrophils, contributed to renal bilateral IRI.

Alpha 7 nicotinic acetylcholine receptors signaling boosts cell-cell interactions in macrophages effecting anti-inflammatory and organ protection.

Activation of the cholinergic anti-inflammatory pathway (CAP) via vagus nerve stimulation has been shown to improve acute kidney injury in rodent models. While alpha 7 nicotinic acetylcholine receptor (α7nAChR) positive macrophages are thought to play a crucial role in this pathway, their in vivo significance has not been fully understood. In this study, we used macrophage-specific α7nAChR-deficient mice to confirm the direct activation of α7nAChRs in macrophages. Our findings indicate that the administration of GTS-21, an α7nAChR-specific agonist, protects injured kidneys in wild-type mice but not in macrophage-specific α7nAChR-deficient mice. To investigate the signal changes or cell reconstructions induced by α7nAChR activation in splenocytes, we conducted single-cell RNA-sequencing of the spleen. Ligand-receptor analysis revealed an increase in macrophage-macrophage interactions. Using macrophage-derived cell lines, we demonstrated that GTS-21 increases cell contact, and that the contact between macrophages receiving α7nAChR signals leads to a reduction in TNF-α. Our results suggest that α7nAChR signaling increases macrophage-macrophage interactions in the spleen and has a protective effect on the kidneys.

Induction of tetraspanin 13 contributes to the synergistic anti-inflammatory effects of parasympathetic and sympathetic stimulation in macrophages.

The autonomic nervous system plays an important role in the regulation of peripheral inflammation. Sympathetic nervous activation stimulates inflammatory gene expression and cytokines, whereas parasympathetic nervous activation suppresses the production of inflammatory cytokines by immune cells. However, most studies on the relationship between the autonomic nervous system and immune processes have analyzed a single branch of the autonomic nerves in isolation. Therefore, this study aimed to examine the effects of sympathetic and parasympathetic stimulation on macrophages, which are controlled by autonomic regulation. Macrophages were stimulated with lipopolysaccharide (LPS) to induce TNF-α. Then, the effects of ß2 adrenergic receptor and α7 nicotinic acetylcholine receptor activation on TNF-α production were assessed using concentration-dependent assays. RNA-seq data were also used to identify genes whose expression was enhanced by parasympathetic and sympathetic stimulation. The simultaneous activation of ß2 adrenergic receptors and α7 nicotinic acetylcholine receptors suppressed LPS-induced TNF-α production in a concentration-dependent manner. Moreover, simultaneous activation of these receptors had synergistic anti-inflammatory effects and induced Tspan13 expression, thereby contributing to anti-inflammatory mechanisms in macrophages. Our study revealed the synergistic anti-inflammatory effects of the parasympathetic and sympathetic stimulation of macrophages. Our results suggest that targeting both sympathetic and parasympathetic signaling is a promising therapeutic approach for inflammatory diseases.

Bone marrow stromal cell antigen-1 (CD157) regulated by sphingosine kinase 2 mediates kidney fibrosis.

Chronic kidney disease is a progressive disease that may lead to end-stage renal disease. Interstitial fibrosis develops as the disease progresses. Therapies that focus on fibrosis to delay or reverse progressive renal failure are limited. We and others showed that sphingosine kinase 2-deficient mice (Sphk2 -/-) develop less fibrosis in mouse models of kidney fibrosis. Sphingosine kinase2 (SphK2), one of two sphingosine kinases that produce sphingosine 1-phosphate (S1P), is primarily located in the nucleus. S1P produced by SphK2 inhibits histone deacetylase (HDAC) and changes histone acetylation status, which can lead to altered target gene expression. We hypothesized that Sphk2 epigenetically regulates downstream genes to induce fibrosis, and we performed a comprehensive analysis using the combination of RNA-seq and ChIP-seq. Bst1/CD157 was identified as a gene that is regulated by SphK2 through a change in histone acetylation level, and Bst1 -/- mice were found to develop less renal fibrosis after unilateral ischemia-reperfusion injury, a mouse model of kidney fibrosis. Although Bst1 is a cell-surface molecule that has a wide variety of functions through its varied enzymatic activities and downstream intracellular signaling pathways, no studies on the role of Bst1 in kidney diseases have been reported previously. In the current study, we demonstrated that Bst1 is a gene that is regulated by SphK2 through epigenetic change and is critical in kidney fibrosis.

Influenza Vaccination and Risk of Lung Cancer in Patients with Chronic Kidney Disease: A Nationwide, Population-Based Cohort Study.

Chronic kidney disease (CKD) is significantly associated with lung cancer incidence. The aim of this study was to elucidate whether influenza vaccination reduces the incidence of lung cancer in patients with CKD. This cohort study enrolled patients with a record of CKD diagnosis from 2000 to 2012 in Taiwan's National Health Insurance Research Database. Included patients were divided into vaccinated and unvaccinated groups. In total 12,985 patients with CKD were enrolled. Among these patients, 5495 were vaccinated and 7490 were unvaccinated. The risk of lung cancer was significantly lower in the influenza vaccination group after adjusting for age, sex, dialysis status, lung diseases, comorbidities, level of urbanization, and monthly income (adjusted hazard ratio (HR): 0.50, 95% confidence interval (CI; 0.38−0.65), p < 0.05). Lower risk of lung cancer was observed in both sexes, all age groups, dialysis status and co-existed lung diseases. The association between the risk of lung cancer and vaccination appeared to be dose-dependent (adjusted HRs: 0.91 (0.66−1.25), 0.49 (0.34−0.71), and 0.25 (0.17−0.38) for patients who received 1, 2 or 3, and ≥4 vaccinations during the follow-up period, respectively). In conclusion, Influenza vaccination decreased the risk of lung cancer in patients diagnosed with CKD. This potentially protective effect against lung cancer appeared to be dose dependent.

The down-regulation of XBP1, an unfolded protein response effector, promotes acute kidney injury to chronic kidney disease transition.

BACKGROUND: The activation of the unfolded protein response (UPR) is closely linked to the pathogenesis of renal injuries. However, the role of XBP1, a crucial regulator of adaptive UPR, remains unclear during the transition from acute kidney injury (AKI) to chronic kidney disease (CKD). METHODS: We characterized XBP1 expressions in different mouse models of kidney injuries, including unilateral ischemia-reperfusion injury (UIRI), unilateral ureteral obstruction, and adenine-induced CKD, followed by generating proximal tubular XBP1 conditional knockout (XBP1cKO) mice for examining the influences of XBP1. Human proximal tubular epithelial cells (HK-2) were silenced of XBP1 to conduct proteomic analysis and investigate the underlying mechanism. RESULTS: We showed a tripartite activation of UPR in injured kidneys. XBP1 expressions were attenuated after AKI and inversely correlated with the severity of post-AKI renal fibrosis. XBP1cKO mice exhibited more severe renal fibrosis in the UIRI model than wide-type littermates. Silencing XBP1 induced HK-2 cell cycle arrest in G2M phase, inhibited cell proliferation, and promoted TGF-ß1 secretion. Proteomic analysis identified TNF receptor associated protein 1 (Trap1) as the potential downstream target transcriptionally regulated by XBP1s. Trap1 overexpression can alleviate silencing XBP1 induced profibrotic factor expressions and cell cycle arrest. CONCLUSION: The loss of XBP1 in kidney injury was profibrotic, and the process was mediated by autocrine and paracrine regulations in combination. The present study identified the XBP1-Trap1 axis as an instrumental mechanism responsible for post-AKI fibrosis, which is a novel regulatory pathway.

Activation of α7 nicotinic acetylcholine receptors attenuates monocyte-endothelial adhesion through FUT7 inhibition.

Cholinergic anti-inflammatory pathway (CAP) describes a neuronal-inflammatory reflex centered on systemic cytokine regulation by α7 nicotinic acetylcholine receptor (α7nAChR) activation of spleen-residue macrophage. However, the CAP mechanism attenuating distal tissue inflammation, inducing a low level of systemic inflammation, is lesser known. In this study, we hypothesized that CAP regulates monocyte accessibility by influencing their adhesion to endothelial cells. Using RNA-seq analysis, we identified that α1,3-Fucosyltransferase 7 (FucT-VII), the enzyme required for processing selectin ligands, was significantly downregulated by α7nAChR agonist among other cell-cell adhesion genes. The α7nAChR agonist inhibited monocytic cell line U-937 binding to P-selectin and adhesion to endothelial cells. Furthermore, α7nAChR agonist selectivity was confirmed by α7nAChR knockdown assays, showing that FUT7 inhibition and adhesion attenuation by the agonist was abolished by siRNA targeting α7nAChR encoding gene. Consistently, FUT7 knockdown inhibited the adhesive properties of U-937 and prevented them to adhere to endothelial cells. Overexpression of FUT7 also abrogated the adhesion attenuation induced by GTS-21 indicating that FUT7 inhibition was sufficient for inhibiting adhesion by α7nAChR activation. Our work demonstrated that α7nAChR activation regulates monocyte adhesion to endothelial cells through FUT7 inhibition, providing a novel insight into the CAP mechanism.

Therapeutic Approaches Targeting Proteostasis in Kidney Disease and Fibrosis.

Pathological insults usually disturb the folding capacity of cellular proteins and lead to the accumulation of misfolded proteins in the endoplasmic reticulum (ER), which leads to so-called "ER stress". Increasing evidence indicates that ER stress acts as a trigger factor for the development and progression of many kidney diseases. The unfolded protein responses (UPRs), a set of molecular signals that resume proteostasis under ER stress, are thought to restore the adaptive process in chronic kidney disease (CKD) and renal fibrosis. Furthermore, the idea of targeting UPRs for CKD treatment has been well discussed in the past decade. This review summarizes the up-to-date literature regarding studies on the relationship between the UPRs, systemic fibrosis, and renal diseases. We also address the potential therapeutic possibilities of renal diseases based on the modulation of UPRs and ER proteostasis. Finally, we list some of the current UPR modulators and their therapeutic potentials.

Activation of Sympathetic Signaling in Macrophages Blocks Systemic Inflammation and Protects against Renal Ischemia-Reperfusion Injury.

BACKGROUND: The sympathetic nervous system regulates immune cell dynamics. However, the detailed role of sympathetic signaling in inflammatory diseases is still unclear because it varies according to the disease situation and responsible cell types. This study focused on identifying the functions of sympathetic signaling in macrophages in LPS-induced sepsis and renal ischemia-reperfusion injury (IRI). METHODS: We performed RNA sequencing of mouse macrophage cell lines to identify the critical gene that mediates the anti-inflammatory effect of ß2-adrenergic receptor (Adrb2) signaling. We also examined the effects of salbutamol (a selective Adrb2 agonist) in LPS-induced systemic inflammation and renal IRI. Macrophage-specific Adrb2 conditional knockout (cKO) mice and the adoptive transfer of salbutamol-treated macrophages were used to assess the involvement of macrophage Adrb2 signaling. RESULTS: In vitro, activation of Adrb2 signaling in macrophages induced the expression of T cell Ig and mucin domain 3 (Tim3), which contributes to anti-inflammatory phenotypic alterations. In vivo, salbutamol administration blocked LPS-induced systemic inflammation and protected against renal IRI; this protection was mitigated in macrophage-specific Adrb2 cKO mice. The adoptive transfer of salbutamol-treated macrophages also protected against renal IRI. Single-cell RNA sequencing revealed that this protection was associated with the accumulation of Tim3-expressing macrophages in the renal tissue. CONCLUSIONS: The activation of Adrb2 signaling in macrophages induces anti-inflammatory phenotypic alterations partially via the induction of Tim3 expression, which blocks LPS-induced systemic inflammation and protects against renal IRI.

Virus Elimination by Direct-Acting Antiviral Agents Impacts Glucose Homeostasis in Chronic Hepatitis C Patients.

Background and Aims: Chronic hepatitis C virus (HCV) infection is associated with dysregulation of glucose homeostasis, including insulin resistance (IR) and type 2 diabetes. However, independent risk factors associated with IR in chronic HCV-infected patients have not been detailly elucidated. Previous data regarding the impact of HCV elimination by direct-acting antiviral agents (DAAs) on glucose homeostasis is insufficient and controversial. This study aimed to analyze the independent factors associated with IR and to evaluate the changes in glucose homeostasis in chronic HCV-infected patients treated with DAAs therapies. Methods: We screened 704 patients with chronic HCV infection who underwent treatment with interferon-free DAAs. Patients' baseline characteristics, biochemical and virological data were collected. The outcome measurements were their IR and ß-cell function assessed by the homeostasis model assessment (HOMA) method at baseline and 12-weeks post-treatment. Results: High IR (HOMA-IR ≥ 2.5) was observed in 35.1% of the patients. Multivariable logistic regression analysis revealed that body mass index (BMI) >25 kg/m2, treatment experience, elevated baseline levels of alanine aminotransferase (ALT) and triglyceride, as well as Fibrosis-4 score >3.25 were independently associated with high IR. In patients who achieved sustained virological response (SVR), no significant change in mean HOMA-IR was observed from baseline to 12-weeks post-treatment (2.74 ± 2.78 to 2.54 ± 2.20, p = 0.128). We observed a significant improvement in ß-cell secretion stress from 121.0 ± 110.1 to 107.6 ± 93.0 (p = 0.015). Subgroup analysis revealed that SVR was associated with a significant reduction in mean HOMA-IR in patients with baseline HOMA-IR ≥ 2.5 (5.31 ± 3.39 to 3.68 ± 2.57, p < 0.001), HCV genotype 1 (3.05 ± 3.11 to 2.62 ± 2.05, p = 0.027), and treatment experience (4.00 ± 3.37 to 3.01 ± 2.49, p = 0.039). Conclusions: There were several independent factors associated with IR in patients with chronic HCV infection, including obesity, treatment experience, high serum ALT and triglyceride levels, as well as advanced hepatic fibrosis. After viral elimination by DAAs, we observed a significant reduction in mean HOMA-IR in patients with baseline high IR, HCV genotype 1, and treatment experience.

Direct-acting antiviral therapy of chronic hepatitis C improves liver fibrosis, assessed by histological examination and laboratory markers.

BACKGROUND/PURPOSE: Direct-acting antiviral agents achieve sustained virological response in most chronic hepatitis C patients. However, histological responses are not consistent among all patients. We conducted an observational study to analyze the histological changes after direct-acting antiviral agent therapy. METHODS: We recruited 220 patients who achieved sustained virological response after direct-acting antiviral agent. Histology was assessed by liver biopsy and laboratory indices including fibrosis-4 and aspartate aminotransferase to platelet ratio index. Primary outcomes were change in the dynamic laboratory results. Secondary outcomes were histological changes on liver biopsy. We analyzed the factors predictive of histological regression. RESULTS: The mean fibrosis-4 index decreased from 4.78 at baseline to 3.30, 3.31, 3.65, and 3.66 at week 4, 8, end of treatment, and 12 weeks after treatment, respectively (all p < 0.01). Mean aspartate aminotransferase to platelet ratio index decreased from 1.62 at baseline to 0.61, 0.66, 0.64, and 0.82 at week 4, 8, end of treatment, and 12 weeks after treatment, respectively (all p < 0.01). Mean Histological Activity Index at baseline and post-treatment was 6.9 ± 1.9 and 5.0 ± 2.3. The METAVIR fibrosis scores improved in 61.9% of the patients. We compared patients who achieved fibrosis-regression with the non-regression group. There was no significant difference in the baseline host/virological factors between the groups. CONCLUSION: Reversal of liver inflammation and fibrosis was achieved in a significant number of patients who received direct-acting antiviral agent. No baseline host or virological factor was predictive of histological regression after antiviral treatment.

Vagus nerve stimulation even after injury ameliorates cisplatin-induced nephropathy via reducing macrophage infiltration.

The efficacy of prior activation of an anti-inflammatory pathway called the cholinergic anti-inflammatory pathway (CAP) through vagus nerve stimulation (VNS) has been reported in renal ischemia-reperfusion injury models. However, there have been no reports that have demonstrated the effectiveness of VNS after injury. We investigated the renoprotective effect of VNS in a cisplatin-induced nephropathy model. C57BL/6 mice were injected with cisplatin, and VNS was conducted 24 hours later. Kidney function, histology, and a kidney injury marker (Kim-1) were evaluated 72 hours after cisplatin administration. To further explore the role of the spleen and splenic macrophages, key players in the CAP, splenectomy, and adoptive transfer of macrophages treated with the selective α7 nicotinic acetylcholine receptor agonist GTS-21 were conducted. VNS treatment significantly suppressed cisplatin-induced kidney injury. This effect was abolished by splenectomy, while adoptive transfer of GTS-21-treated macrophages improved renal outcomes. VNS also reduced the expression of cytokines and chemokines, including CCL2, which is a potent chemokine attracting monocytes/macrophages, accompanied by a decline in the number of infiltrating macrophages. Taken together, stimulation of the CAP protected the kidney even after injury in a cisplatin-induced nephropathy model. Considering the feasibility and anti-inflammatory effects of VNS, the findings suggest that VNS may be a promising therapeutic tool for acute kidney injury.

Subgroup analysis of the predictive ability of aspartate aminotransferase to platelet ratio index (APRI) and fibrosis-4 (FIB-4) for assessing hepatic fibrosis among patients with chronic hepatitis C.

BACKGROUND: There are many laboratory indices to assess liver fibrosis. Aspartate aminotransferase to platelet ratio index (APRI) and fibrosis-4 (FIB-4) index have been used as well-known serum markers of liver fibrosis. With the increasing use of non-invasive fibrosis assessment, it is important to recognize the limitations of these tests. The factors influencing the diagnostic accuracy to evaluate liver fibrosis are not well-established. This study aimed to perform a subgroup analysis of the predictive ability of laboratory indices. METHODS: Overall, 113 patients with chronic hepatitis C infection who underwent liver biopsy were retrospectively examined. The histological assessment of liver fibrosis was performed using the METAVIR scoring system, and the values of several laboratory tests were also evaluated on the same day. We categorized our study population by treatment status, body mass index (BMI), and age. RESULTS: The two laboratory indices APRI and FIB-4 index could predict advanced (F3-4) liver fibrosis and cirrhosis (F4), with the area under the receiver operating characteristic curve (AUROC) > 0.8 and accuracy >70%. The AUROCs and accuracies were higher among patients with sustained virological response (SVR) than among those without SVR. A higher predictive ability was also observed among patients with BMI <25 kg/m2. Age did not appear to affect liver fibrosis predictability. CONCLUSIONS: The laboratory indices APRI and FIB-4 index exhibit good diagnostic performance for determining advanced fibrosis and cirrhosis among patients with hepatitis C infection. The diagnostic accuracy appears better among patients with SVR and those with BMI <25 kg/m2.

ATF6α downregulation of PPARα promotes lipotoxicity-induced tubulointerstitial fibrosis.

Tubulointerstitial fibrosis is a strong predictor of progression in patients with chronic kidney disease, and is often accompanied by lipid accumulation in renal tubules. However, the molecular mechanisms modulating the relationship between lipotoxicity and tubulointerstitial fibrosis remain obscure. ATF6α, a transcription factor of the unfolded protein response, is reported to be an upstream regulator of fatty acid metabolism. Owing to their high energy demand, proximal tubular cells (PTCs) use fatty acids as their main energy source. We therefore hypothesized that ATF6α regulates PTC fatty acid metabolism, contributing to lipotoxicity-induced tubulointerstitial fibrosis. Overexpression of activated ATF6α transcriptionally downregulated peroxisome proliferator-activated receptor-α (PPARα), the master regulator of lipid metabolism, leading to reduced activity of fatty acid ß-oxidation and cytosolic accumulation of lipid droplets in a human PTC line (HK-2). ATF6α-induced lipid accumulation caused mitochondrial dysfunction, enhanced apoptosis, and increased expression of connective tissue growth factor (CTGF), as well as reduced cell viability. Atf6α-/- mice had sustained expression of PPARα and less tubular lipid accumulation following unilateral ischemia-reperfusion injury (uIRI), resulting in the amelioration of apoptosis; reduced expression of CTGF, α-smooth muscle actin, and collagen I; and less tubulointerstitial fibrosis. Administration of fenofibrate, a PPARα agonist, reduced lipid accumulation and tubulointerstitial fibrosis in the uIRI model. Taken together, these findings suggest that ATF6α deranges fatty acid metabolism in PTCs, which leads to lipotoxicity-mediated apoptosis and CTGF upregulation, both of which promote tubulointerstitial fibrosis.

Long-term histological change in chronic hepatitis C patients who had received peginterferon plus ribavirin therapy with sustained virological response.

BACKGROUND: The improvement in liver histology is an important aim in the management of hepatitis C virus (HCV) infection. Previous studies suggest that antiviral treatment could reduce the progression of hepatic fibrosis, especially in patients with sustained virological response (SVR). However, most studies were limited by short-term evaluations and the liver stiffness was assessed by non-invasive methods. In our study, we performed a paired liver biopsy study aimed at analyzing the long-term histological changes in patients with SVR. METHODS: We included 31 patients who had been previously treated with peginterferon plus ribavirin. All patients achieved SVR and had received pre- and post-treatment liver biopsies. The histological appearance of fibrosis and inflammation were assessed with METAVIR scoring system and Histological Activity Index (HAI) criteria. We analyzed several factors associated with the histological response. RESULTS: The median interval between two biopsies was 93.0 months. The percentage of patients with fibrosis regression, stable, and progression were 19%, 45%, and 36%. A total of 71% of patients achieved inflammation improvement, whereas 6% and 23% of patients had stable disease and disease-progression, respectively. We showed that the patients without baseline advanced fibrosis and those having a lower baseline HAI score had higher risk of fibrosis worsening. Baseline fibrosis and necroinflammation status did not influence HAI change significantly. CONCLUSION: The progression of hepatic fibrosis and inflammation can be reversed in some patients who had long-term virological suppression. Patients with advanced baseline fibrosis and higher inflammatory stages seemed to receive more histologic benefit from successful antiviral treatments.

Palmitate deranges erythropoietin production via transcription factor ATF4 activation of unfolded protein response.

Lipotoxicity plays an important role in the progression of chronic kidney damage via various mechanisms, such as endoplasmic reticulum stress. Several studies proposed renal lipotoxicity in glomerular and tubular cells but the effect of lipid on renal erythropoietin (EPO)-producing (REP) cells in the interstitium has not been elucidated. Since renal anemia is caused by derangement of EPO production in REP cells, we evaluated the effect of palmitate, a representative long-chain saturated fatty acid, on EPO production and the endoplasmic reticulum stress pathway. EPO production was suppressed by palmitate (palmitate-conjugated bovine serum albumin [BSA]) or a high palmitate diet, but not oleic acid-conjugated BSA or a high oleic acid diet, especially under cobalt-induced pseudo-hypoxia both in vitro and in vivo. Importantly, suppression of EPO production was not induced by a decrease in transcription factor HIF activity, while it was significantly associated with endoplasmic reticulum stress, particularly transcription factor ATF4 activation, which suppresses 3'-enhancer activity of the EPO gene. ATF4 knockdown by siRNA significantly attenuated the suppressive effect of palmitate on EPO production. Studies utilizing inherited super-anemic mice (ISAM) mated with EPO-Cre mice (ISAM-REC mice) for lineage-labeling of REP cells showed that ATF4 activation by palmitate suppressed EPO production in REP cells. Laser capture microdissection confirmed ATF4 activation in the interstitial area of ISAM-REC mice treated with palmitate-conjugated BSA. Thus, endoplasmic reticulum stress induced by palmitate suppressed EPO expression by REP cells in a manner independent of HIF activation. The link between endoplasmic reticulum stress, dyslipidemia, and hypoxia may contribute to development and progression of anemia in CKD.

Genotype distribution and treatment response among incarcerated drug-dependent patients with chronic hepatitis C infection.

The prevalence of hepatitis C virus (HCV) infection is disproportionately high among prisoners, especially among those who are drug-dependent. However, current screening and treatment recommendations are inconsistent for this population, and appropriate care is not reliably provided. To address these problems, the present study aimed to identify unique characteristics and clinical manifestations of incarcerated patients with HCV infection. We included incarcerated patients who received treatment with pegylated-interferon combined with ribavirin at Mackay Memorial Hospital in Taitung and were serving sentences at either the Taiyuan Skill Training Institute or the Yanwan Training Institute. HCV genotypes 1 (41.4%), 3 (25.9%), and 6 (24.1%) were the most prevalent in the incarcerated patients. During the study period, we analyzed treatment response among 58 incarcerated patients and compared obtained results with treatment response among 52 patients who were living in the community. Higher sustained virological response rate was observed among patients with incarceration and HCV genotype other than 1. The odds ratios (corresponding 95% confidence intervals) for incarceration and genotype 1 were 2.75 (1.06-7.11) and 0.37 (0.14-0.99), respectively. Better treatment compliance among incarcerated patients might partially explain these results. The results of this study suggest that treatment of prisoners with HCV infection is feasible and effective. More appropriate and timely methods are needed to prevent HCV transmission among injection drug users inside prisons.

High frequencies of a favorable IL-28B rs8099917 polymorphism and the clinical implications in patients with HCV in one multiracial area of Taiwan.

There is a strong association between hepatitis C virus (HCV) treatment efficacy and the interleukin (IL)-28B gene. However, the IL-28B variant's distribution and potential role in the therapeutic response are not well established in Taitung, a racially diverse county in Taiwan. Here, we investigated the distribution pattern of IL-28B rs8099917 and its influence on treatment efficacy. In this retrospective study, we enrolled 180 patients who had been treated with pegylated-interferon plus ribavirin. Patients' general information, virological characteristics, IL-28B status, laboratory results, treatment course, and outcome were analyzed. Of the patients enrolled, 56.7% were male, with a mean age of 54.11 years. A total of 24.4% of the population were indigenous people. The majority of patients had the favorable IL-28B polymorphism (rs8099917 TT/TG/GG: 94.4%/5.6%/0%). The proportion of patients with the TT genotype seemed to be higher in indigenous patients. The rate of sustained virological response (SVR) among included patients was 73.0%. Univariate analysis showed that genotype non-1, patients achieved rapid virological response (RVR), lower body mass index (BMI), and lower baseline HCV viral load were significantly associated with SVR. Multivariate analysis revealed that BMI <25 and RVR are the independent predictor of success treatment. In conclusion, the favorable IL-28B rs8099917 polymorphism occurs in high frequency in this multiracial area, which might be important to help guide physicians and patients in their future clinical decisions.